Director of PT Kereta Cepat Indonesia China director (KCIC) explains problem of the Jakarta-Bandung high-speed train tunnel.

He say "Tunnel 2 is in the clay shale area. More complex handling". He say clay shale layer is weak. It is feared that it move embankment construction and road construction above it. Therefore special handling is necessary.

Therefore KCIC bring 33 tunnel experts from China to to solve problem. Also help from ITB. There are also 17 grouting experts to make ground stronger.

https://ekonomi.bisnis.com/read/20220110/98/1487392/ini-penjelasan-bos-kcic-soal-masalah-terowongan-kereta-cepat-jakarta-bandung